The Pacemaker-Lead System
When the heart fails to beat or beats irregularly, physicians may implant a pacemaker to ensure the regular beat of the heart. Pacemakers have implantable electrical leads, i.e., specially coated wires with electrodes at the tip that connect the pacemaker to the heart, usually to its inner wall via the venous system. FIG. 1 depicts a pacemaker 10 and an implantable lead 20. The pacemaker senses electrical activity and sends an electrical current through the implantable lead to the heart at appropriate intervals to regulate the heartbeat. The distal (i.e., most distant from the pacemaker) end 24 of the lead 20 is located typically on the endocardium of the heart. The proximal (i.e., closest to the pacemaker) end 22 of the lead 20 generally has a single or multiple coaxial contact assembly for insertion into and electrical coupling with pacemaker 10.